I should point out, however, that at first some difficulty was experienced in observing the phenomena predicted by the theory, owing to the extreme smallness of the variations in the period of oscillation.
-- Pieter Zeeman
   
Pieter Zeeman   Name:
Pieter Zeeman
Type:
Physicist
Nationality:
Dutch
Birth:
May 25, 1865
Death:
October 9, 1943
https://www.nutquote.com/quote/Pieter_Zeeman